Our future goals include: 1) Extension of our successful efforts to achieve direct routes to K-region arene oxides, including those bearing oxiranyl rings flanked by substituents. 2. Expansion of our program in the area of oxygen transfer reactions to nitrogen bases and sulfur compounds and defining the scope and mechanism and the possible significance of this process in chemical carcinogenesis. During this report period little progress had been achieved in this significant area as a result of student interest and efforts in the area of direct oxidation of PNAH's. 3) Investigations continue on the photochemical properties of arene oxides. In particular we are interested in their photorearrangement to oxepins as well as photoreaction with nucleophiles and the significance of these reactions in the solar induction of skin cancer. 4) Synthesis of radio-labeled oxiranes such a 9-14C, 10-phenanthrene oxide using standard ground state and photochemical reactions to prepare the labeled phenanthrene which may be oxidized to 9-14C, 10-phenanthrene oxide for utilization in the assay of the enzyme hydratase. 5) Continued cooperation with Profs. Mary and Joseph Arcos on the structural elucidation of rat metabolites such as those derived from the hepatic carcinogen dioxane. Present efforts are concentrated on the properties of the 2,3,4,5-tetrachlorodioxanes which based on dichloro analogs could be highly mutagenic and/or carcinogenic. 6) Comparison of rat metabolites of naphthalene (the simplest PNAH) with hydrolysis products of anti-1,2:3,4-naphthalene dioxide obtained during the course of our direct oxide studies is also of high priority.